Energy Consumption and Scalability of Transmitting Firmware Updates Over LoRa

Abstract

The rapid growth of LoRa sensor networks lead to more and more maintenence challenges. One of them is wirelessly updating the firmware, especially for the ones that are hard or dangerous to reach. Is it feasible to do a firmware update over LoRa, and what is its additional power consumption of the wireless sensors? In this thesis a LoRa Class B Firmware Update Over The Air (FUOTA) is implemented and evaluated. Up to 100 end-devices are used to research the scalibilities and power consumption of the end-devices. The focus is mainly on the tranmission of the firmware itself rather than installing the firmware on the end-devices.
This study introduces a power consumption model based on measurements of real hardware. After that, experiments are performed to evaluate the packet losses when scaling up the number of end-devices. These experiments show that the setup time increases with the number of end-devices due to the duty cycle restriction of the gateway. Antother experiment, focusing on end-devices that are part of the network but do not need to be updated, shows these end-devices suffer in terms of packets loss due to packet blockings during a firmware update.
The extra setup time needed when scaling up the number of end-devices causes higher power consumption when more devices needs to be updates. To reduce the energy consumption during this setup phase, an improvement to the communciation protocol is presentated at the end of this thesis. It reduces the number of times receive windows are opened while nothing is send.